Still waiting for her confirmation hearing more than four months after she was nominated, President Obama’s pick to be the U.S. ambassador to Mexico withdrew her nomination earlier this week.

Maria Echaveste, whose parents were Mexican immigrants, would have been the first woman to have the post.

The White House confirmed her decision to the Loop, which was first reported by Politico. Eric Schultz, White House spokesman, said she “cited the prolonged confirmation process and her family’s best interests in her request.”

“Echaveste is a proven leader and a renowned expert on U.S.– Mexico policy with a strong record of public service,” he said. “While the President regrets the long delays in this confirmation process that have led her to this decision, he accepts it and wishes her all the best in future endeavors.”

Echaveste was Bill Clinton’s deputy chief of staff, is a supporter of Hillary Rodham Clinton and an advocate for immigration reform — which all would have made her a target in the now Republican-controlled Senate.

President Bill Clinton goes over his 1999 State of the Union speech with speech writer Michael Waldman and Deputy Chief of Staff Maria Echaveste in the Oval Office. (Rick Bowmer/The Washington Post)

When she was first nominated in September, Post Mexico correspondent Joshua Partlow wrote about the strengths she’d bring, but also the challenges she’d face running one of the United States’ largest embassy staffs, in a country with so many critical issues like trade and border security.

Partlow at the time quoted one professor who commended the pick because of Echaveste’s bicultural background, while a Mexican journalist saw it as a way for the White House “to fill quotas.”

Echaveste, whose husband, Christopher Edley, instructed Obama at Harvard Law School, was considered a political appointment because she is not in the foreign service. Although the Democrat-controlled Senate cleared many ambassadorial nominees in the 2014 lame duck session before handing over the majority, Echaveste’s nomination was caught in the backlog. For those who didn’t get through last year, Obama must re-nominate them.

As we’ve written before, for would-be ambassadors, the uncertainty of waiting to find out if and when you are uprooting your life and moving to a new country can be trying. Some were in limbo more than a year.